Loading up logitech gaming software to set some color. get color (blue):

Setup Data
    bmRequestType: 0x21
        0... .... = Direction: Host-to-device
        .01. .... = Type: Class (0x1)
        ...0 0001 = Recipient: Interface (0x01)
    bRequest: SET_REPORT (0x09)
    wValue: 0x0307
        ReportID: 7
        ReportType: Feature (3)
    wIndex: 0
    wLength: 5
    bRequest: 9
    wValue: 0x0307
    wIndex: 0 (0x0000)
    wLength: 5
    Data Fragment: 070000ff00

blue:: 07 00 00 ff 00
red?: 07 55 ff 00 00
green?: 07 ff 00 00 00
white: 07 6e ff 5a 00 I guess color correction is done in logitech gaming software...
off: 07 00 00 00 00

macro keys are on endpoint 5, and packed into a single byte:

Setup Data
    bmRequestType: 0x21
        0... .... = Direction: Host-to-device
        .01. .... = Type: Class (0x1)
        ...0 0001 = Recipient: Interface (0x01)
    bRequest: SET_REPORT (0x09)
    wValue: 0x0305
        ReportID: 5
        ReportType: Feature (3)
    wIndex: 0
    wLength: 5
    bRequest: 9
    wValue: 0x0305
    wIndex: 0 (0x0000)
    wLength: 5
    Data Fragment: 0501000000

Success? partially